Reimplement the linked list data structure used throughout the backend.

In the past, we used a 'Lispy' linked list implementation: a "list" was merely a pointer to the head node of the list. The problem with that design is that it makes lappend() and length() linear time. This patch fixes that problem (and others) by maintaining a count of the list length and a pointer to the tail node along with each head node pointer. A "list" is now a pointer to a structure containing some meta-data about the list; the head and tail pointers in that structure refer to ListCell structures that maintain the actual linked list of nodes. The function names of the list API have also been changed to, I hope, be more logically consistent. By default, the old function names are still available; they will be disabled-by-default once the rest of the tree has been updated to use the new API names.
2025-07-18 17:42:25 +03:00 · 2004-05-26 04:41:50 +00:00
parent 18d0d10563
commit d0b4399d81
125 changed files with 3639 additions and 3038 deletions
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@ -6,7 +6,7 @@
 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
- *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.300 2004/05/23 17:10:54 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.301 2004/05/26 04:41:29 neilc Exp $
 *
 *-------------------------------------------------------------------------
 */
@ -240,28 +240,20 @@ do_parse_analyze(Node *parseTree, ParseState *pstate)
 	List	   *extras_before = NIL;
 	List	   *extras_after = NIL;
 	Query	   *query;
-	List	   *listscan;
+	ListCell   *l;

 	query = transformStmt(pstate, parseTree, &extras_before, &extras_after);

 	/* don't need to access result relation any more */
 	release_pstate_resources(pstate);

-	while (extras_before != NIL)
-	{
-		result = nconc(result,
-					   parse_sub_analyze(lfirst(extras_before), pstate));
-		extras_before = lnext(extras_before);
-	}
+	foreach(l, extras_before)
+		result = nconc(result, parse_sub_analyze(lfirst(l), pstate));

 	result = lappend(result, query);

-	while (extras_after != NIL)
-	{
-		result = nconc(result,
-					   parse_sub_analyze(lfirst(extras_after), pstate));
-		extras_after = lnext(extras_after);
-	}
+	foreach(l, extras_after)
+		result = nconc(result, parse_sub_analyze(lfirst(l), pstate));

 	/*
 	 * Make sure that only the original query is marked original. We have
@ -270,9 +262,9 @@ do_parse_analyze(Node *parseTree, ParseState *pstate)
 	 * mark only the original query as allowed to set the command-result
 	 * tag.
 	 */
-	foreach(listscan, result)
+	foreach(l, result)
 	{
-		Query	   *q = lfirst(listscan);
+		Query	   *q = lfirst(l);

 		if (q == query)
 		{
@ -428,8 +420,8 @@ transformViewStmt(ParseState *pstate, ViewStmt *stmt,
 	 */
 	if (stmt->aliases != NIL)
 	{
-		List	   *aliaslist = stmt->aliases;
-		List	   *targetList;
+		ListCell	   *alist_item = list_head(stmt->aliases);
+		ListCell	   *targetList;

 		foreach(targetList, stmt->query->targetList)
 		{
@ -442,13 +434,13 @@ transformViewStmt(ParseState *pstate, ViewStmt *stmt,
 			/* junk columns don't get aliases */
 			if (rd->resjunk)
 				continue;
-			rd->resname = pstrdup(strVal(lfirst(aliaslist)));
-			aliaslist = lnext(aliaslist);
-			if (aliaslist == NIL)
+			rd->resname = pstrdup(strVal(lfirst(alist_item)));
+			alist_item = lnext(alist_item);
+			if (alist_item == NULL)
 				break;		/* done assigning aliases */
 		}

-		if (aliaslist != NIL)
+		if (alist_item != NULL)
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
 					 errmsg("CREATE VIEW specifies more column "
@ -506,9 +498,9 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
 	List	   *sub_namespace;
 	List	   *icolumns;
 	List	   *attrnos;
-	List	   *icols;			/* to become ListCell */
-	List	   *attnos;			/* to become ListCell */
-	List	   *tl;
+	ListCell   *icols;
+	ListCell   *attnos;
+	ListCell   *tl;

 	qry->commandType = CMD_INSERT;
 	pstate->p_is_insert = true;
@ -666,14 +658,14 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
 	/*
 	 * Prepare columns for assignment to target table.
 	 */
-	icols = icolumns;
-	attnos = attrnos;
+	icols = list_head(icolumns);
+	attnos = list_head(attrnos);
 	foreach(tl, qry->targetList)
 	{
 		TargetEntry *tle = (TargetEntry *) lfirst(tl);
 		ResTarget  *col;

-		if (icols == NIL || attnos == NIL)
+		if (icols == NULL || attnos == NULL)
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
 			 errmsg("INSERT has more expressions than target columns")));
@ -694,7 +686,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt,
 	 * present in the columns list.  Don't do the check unless an explicit
 	 * columns list was given, though.
 	 */
-	if (stmt->cols != NIL && (icols != NIL || attnos != NIL))
+	if (stmt->cols != NIL && (icols != NULL || attnos != NULL))
 		ereport(ERROR,
 				(errcode(ERRCODE_SYNTAX_ERROR),
 			 errmsg("INSERT has more target columns than expressions")));
@ -810,7 +802,7 @@ transformCreateStmt(ParseState *pstate, CreateStmt *stmt,
 {
 	CreateStmtContext cxt;
 	Query	   *q;
-	List	   *elements;
+	ListCell   *elements;

 	cxt.stmtType = "CREATE TABLE";
 	cxt.relation = stmt->relation;
@ -895,7 +887,7 @@ transformColumnDefinition(ParseState *pstate, CreateStmtContext *cxt,
 	bool		is_serial;
 	bool		saw_nullable;
 	Constraint *constraint;
-	List	   *clist;
+	ListCell   *clist;

 	cxt->columns = lappend(cxt->columns, column);

@ -903,7 +895,7 @@ transformColumnDefinition(ParseState *pstate, CreateStmtContext *cxt,
 	is_serial = false;
 	if (length(column->typename->names) == 1)
 	{
-		char	   *typname = strVal(lfirst(column->typename->names));
+		char	   *typname = strVal(linitial(column->typename->names));

 		if (strcmp(typname, "serial") == 0 ||
 			strcmp(typname, "serial4") == 0)
@ -1256,13 +1248,10 @@ transformInhRelation(ParseState *pstate, CreateStmtContext *cxt,
 static void
 transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
 {
-	List	   *listptr;
-	List	   *keys;
 	IndexStmt  *index;
-	IndexElem  *iparam;
-	ColumnDef  *column;
-	List	   *columns;
 	List	   *indexlist = NIL;
+	ListCell   *listptr;
+	ListCell   *l;

 	/*
 	 * Run through the constraints that need to generate an index. For
@ -1273,6 +1262,8 @@ transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
 	foreach(listptr, cxt->ixconstraints)
 	{
 		Constraint *constraint = lfirst(listptr);
+		ListCell   *keys;
+		IndexElem  *iparam;

 		Assert(IsA(constraint, Constraint));
 		Assert((constraint->contype == CONSTR_PRIMARY)
@ -1317,11 +1308,12 @@ transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
 		{
 			char	   *key = strVal(lfirst(keys));
 			bool		found = false;
+			ColumnDef  *column = NULL;
+			ListCell   *columns;

-			column = NULL;
 			foreach(columns, cxt->columns)
 			{
-				column = lfirst(columns);
+				column = (ColumnDef *) lfirst(columns);
 				Assert(IsA(column, ColumnDef));
 				if (strcmp(column->colname, key) == 0)
 				{
@ -1347,11 +1339,11 @@ transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
 			else if (cxt->inhRelations)
 			{
 				/* try inherited tables */
-				List	   *inher;
+				ListCell   *inher;

 				foreach(inher, cxt->inhRelations)
 				{
-					RangeVar   *inh = lfirst(inher);
+					RangeVar   *inh = (RangeVar *) lfirst(inher);
 					Relation	rel;
 					int			count;

@ -1447,41 +1439,40 @@ transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
 		/* Make sure we keep the PKEY index in preference to others... */
 		cxt->alist = makeList1(cxt->pkey);
 	}
-	while (indexlist != NIL)
+
+	foreach(l, indexlist)
 	{
-		index = lfirst(indexlist);
+		bool		keep = true;
+		ListCell   *k;
+
+		index = lfirst(l);

 		/* if it's pkey, it's already in cxt->alist */
-		if (index != cxt->pkey)
+		if (index == cxt->pkey)
+			continue;
+
+		foreach(k, cxt->alist)
 		{
-			bool		keep = true;
-			List	   *priorlist;
+			IndexStmt  *priorindex = lfirst(k);

-			foreach(priorlist, cxt->alist)
+			if (equal(index->indexParams, priorindex->indexParams))
 			{
-				IndexStmt  *priorindex = lfirst(priorlist);
-
-				if (equal(index->indexParams, priorindex->indexParams))
-				{
-					/*
-					 * If the prior index is as yet unnamed, and this one
-					 * is named, then transfer the name to the prior
-					 * index. This ensures that if we have named and
-					 * unnamed constraints, we'll use (at least one of)
-					 * the names for the index.
-					 */
-					if (priorindex->idxname == NULL)
-						priorindex->idxname = index->idxname;
-					keep = false;
-					break;
-				}
+				/*
+				 * If the prior index is as yet unnamed, and this one
+				 * is named, then transfer the name to the prior
+				 * index. This ensures that if we have named and
+				 * unnamed constraints, we'll use (at least one of)
+				 * the names for the index.
+				 */
+				if (priorindex->idxname == NULL)
+					priorindex->idxname = index->idxname;
+				keep = false;
+				break;
 			}
-
-			if (keep)
-				cxt->alist = lappend(cxt->alist, index);
 		}

-		indexlist = lnext(indexlist);
+		if (keep)
+			cxt->alist = lappend(cxt->alist, index);
 	}
 }

@ -1489,7 +1480,7 @@ static void
 transformFKConstraints(ParseState *pstate, CreateStmtContext *cxt,
 					   bool skipValidation, bool isAddConstraint)
 {
-	List	   *fkclist;
+	ListCell   *fkclist;

 	if (cxt->fkconstraints == NIL)
 		return;
@ -1550,7 +1541,7 @@ transformIndexStmt(ParseState *pstate, IndexStmt *stmt)
 {
 	Query	   *qry;
 	RangeTblEntry *rte = NULL;
-	List	   *l;
+	ListCell   *l;

 	qry = makeNode(Query);
 	qry->commandType = CMD_UTILITY;
@ -1721,15 +1712,15 @@ transformRuleStmt(ParseState *pstate, RuleStmt *stmt,
 	}
 	else
 	{
-		List	   *oldactions;
+		ListCell   *l;
 		List	   *newactions = NIL;

 		/*
 		 * transform each statement, like parse_sub_analyze()
 		 */
-		foreach(oldactions, stmt->actions)
+		foreach(l, stmt->actions)
 		{
-			Node	   *action = (Node *) lfirst(oldactions);
+			Node	   *action = (Node *) lfirst(l);
 			ParseState *sub_pstate = make_parsestate(pstate->parentParseState);
 			Query	   *sub_qry,
 					   *top_subqry;
@ -1986,9 +1977,9 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	Node	   *limitCount;
 	List	   *forUpdate;
 	Node	   *node;
-	List	   *lefttl,
-			   *dtlist,
-			   *targetvars,
+	ListCell   *left_tlist,
+			   *dtlist;
+	List	   *targetvars,
 			   *targetnames,
 			   *sv_namespace,
 			   *sv_rtable;
@ -2067,15 +2058,17 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 	qry->targetList = NIL;
 	targetvars = NIL;
 	targetnames = NIL;
-	lefttl = leftmostQuery->targetList;
+	left_tlist = list_head(leftmostQuery->targetList);
+
 	foreach(dtlist, sostmt->colTypes)
 	{
 		Oid			colType = lfirsto(dtlist);
-		Resdom	   *leftResdom = ((TargetEntry *) lfirst(lefttl))->resdom;
+		Resdom	   *leftResdom;
 		char	   *colName;
 		Resdom	   *resdom;
 		Expr	   *expr;

+		leftResdom = ((TargetEntry *) lfirst(left_tlist))->resdom;
 		Assert(!leftResdom->resjunk);
 		colName = pstrdup(leftResdom->resname);
 		resdom = makeResdom((AttrNumber) pstate->p_next_resno++,
@ -2092,7 +2085,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
 								  makeTargetEntry(resdom, expr));
 		targetvars = lappend(targetvars, expr);
 		targetnames = lappend(targetnames, makeString(colName));
-		lefttl = lnext(lefttl);
+		left_tlist = lnext(left_tlist);
 	}

 	/*
@ -2239,7 +2232,7 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
 		selectList = parse_sub_analyze((Node *) stmt, pstate);

 		Assert(length(selectList) == 1);
-		selectQuery = (Query *) lfirst(selectList);
+		selectQuery = (Query *) linitial(selectList);
 		Assert(IsA(selectQuery, Query));

 		/*
@ -2282,6 +2275,8 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
 		SetOperationStmt *op = makeNode(SetOperationStmt);
 		List	   *lcoltypes;
 		List	   *rcoltypes;
+		ListCell   *l;
+		ListCell   *r;
 		const char *context;

 		context = (stmt->op == SETOP_UNION ? "UNION" :
@ -2308,18 +2303,17 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
 					(errcode(ERRCODE_SYNTAX_ERROR),
 			 errmsg("each %s query must have the same number of columns",
 					context)));
+
 		op->colTypes = NIL;
-		while (lcoltypes != NIL)
+		forboth(l, lcoltypes, r, rcoltypes)
 		{
-			Oid			lcoltype = lfirsto(lcoltypes);
-			Oid			rcoltype = lfirsto(rcoltypes);
+			Oid			lcoltype = lfirsto(l);
+			Oid			rcoltype = lfirsto(r);
 			Oid			rescoltype;

 			rescoltype = select_common_type(makeListo2(lcoltype, rcoltype),
 											context);
 			op->colTypes = lappendo(op->colTypes, rescoltype);
-			lcoltypes = lnext(lcoltypes);
-			rcoltypes = lnext(rcoltypes);
 		}

 		return (Node *) op;
@ -2339,7 +2333,7 @@ getSetColTypes(ParseState *pstate, Node *node)
 		RangeTblEntry *rte = rt_fetch(rtr->rtindex, pstate->p_rtable);
 		Query	   *selectQuery = rte->subquery;
 		List	   *result = NIL;
-		List	   *tl;
+		ListCell   *tl;

 		Assert(selectQuery != NULL);
 		/* Get types of non-junk columns */
@ -2373,22 +2367,25 @@ getSetColTypes(ParseState *pstate, Node *node)
 static void
 applyColumnNames(List *dst, List *src)
 {
+	ListCell *dst_item = list_head(dst);
+	ListCell *src_item = list_head(src);
+
 	if (length(src) > length(dst))
 		ereport(ERROR,
 				(errcode(ERRCODE_SYNTAX_ERROR),
 			 errmsg("CREATE TABLE AS specifies too many column names")));

-	while (src != NIL && dst != NIL)
+	while (src_item != NULL && dst_item != NULL)
 	{
-		TargetEntry *d = (TargetEntry *) lfirst(dst);
-		ColumnDef  *s = (ColumnDef *) lfirst(src);
+		TargetEntry *d = (TargetEntry *) lfirst(dst_item);
+		ColumnDef  *s = (ColumnDef *) lfirst(src_item);

 		Assert(d->resdom && !d->resdom->resjunk);

 		d->resdom->resname = pstrdup(s->colname);

-		dst = lnext(dst);
-		src = lnext(src);
+		dst_item = lnext(dst_item);
+		src_item = lnext(src_item);
 	}
 }

@ -2402,8 +2399,8 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 {
 	Query	   *qry = makeNode(Query);
 	Node	   *qual;
-	List	   *origTargetList;
-	List	   *tl;
+	ListCell   *origTargetList;
+	ListCell   *tl;

 	qry->commandType = CMD_UPDATE;
 	pstate->p_is_update = true;
@ -2441,7 +2438,8 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 		pstate->p_next_resno = pstate->p_target_relation->rd_rel->relnatts + 1;

 	/* Prepare non-junk columns for assignment to target table */
-	origTargetList = stmt->targetList;
+	origTargetList = list_head(stmt->targetList);
+
 	foreach(tl, qry->targetList)
 	{
 		TargetEntry *tle = (TargetEntry *) lfirst(tl);
@ -2460,7 +2458,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
 			resnode->resname = NULL;
 			continue;
 		}
-		if (origTargetList == NIL)
+		if (origTargetList == NULL)
 			elog(ERROR, "UPDATE target count mismatch --- internal error");
 		origTarget = (ResTarget *) lfirst(origTargetList);

@ -2471,7 +2469,7 @@ transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)

 		origTargetList = lnext(origTargetList);
 	}
-	if (origTargetList != NIL)
+	if (origTargetList != NULL)
 		elog(ERROR, "UPDATE target count mismatch --- internal error");

 	return qry;
@ -2487,7 +2485,7 @@ transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt,
 {
 	CreateStmtContext cxt;
 	Query	   *qry;
-	List	   *lcmd,
+	ListCell   *lcmd,
 			   *l;
 	List	   *newcmds = NIL;
 	bool		skipValidation = true;
@ -2687,7 +2685,7 @@ transformPrepareStmt(ParseState *pstate, PrepareStmt *stmt)

 	if (nargs)
 	{
-		List	   *l;
+		ListCell   *l;
 		int			i = 0;

 		argtoids = (Oid *) palloc(nargs * sizeof(Oid));
@ -2717,7 +2715,7 @@ transformPrepareStmt(ParseState *pstate, PrepareStmt *stmt)
 	if (length(queries) != 1)
 		elog(ERROR, "unexpected extra stuff in prepared statement");

-	stmt->query = lfirst(queries);
+	stmt->query = linitial(queries);

 	return result;
 }
@ -2737,7 +2735,7 @@ transformExecuteStmt(ParseState *pstate, ExecuteStmt *stmt)
 	{
 		int			nparams = length(stmt->params);
 		int			nexpected = length(paramtypes);
-		List	   *l;
+		ListCell   *l, *l2;
 		int			i = 1;

 		if (nparams != nexpected)
@ -2748,11 +2746,11 @@ transformExecuteStmt(ParseState *pstate, ExecuteStmt *stmt)
 					 errdetail("Expected %d parameters but got %d.",
 							   nexpected, nparams)));

-		foreach(l, stmt->params)
+		forboth(l, stmt->params, l2, paramtypes)
 		{
 			Node	   *expr = lfirst(l);
-			Oid			expected_type_id,
-						given_type_id;
+			Oid			expected_type_id = lfirsto(l2);
+			Oid			given_type_id;

 			expr = transformExpr(pstate, expr);

@ -2767,7 +2765,6 @@ transformExecuteStmt(ParseState *pstate, ExecuteStmt *stmt)
 				   errmsg("cannot use aggregate function in EXECUTE parameter")));

 			given_type_id = exprType(expr);
-			expected_type_id = lfirsto(paramtypes);

 			expr = coerce_to_target_type(pstate, expr, given_type_id,
 										 expected_type_id, -1,
@ -2784,8 +2781,6 @@ transformExecuteStmt(ParseState *pstate, ExecuteStmt *stmt)
 						 errhint("You will need to rewrite or cast the expression.")));

 			lfirst(l) = expr;
-
-			paramtypes = lnext(paramtypes);
 			i++;
 		}
 	}
@ -2825,13 +2820,13 @@ static void
 transformForUpdate(Query *qry, List *forUpdate)
 {
 	List	   *rowMarks = qry->rowMarks;
-	List	   *l;
-	List	   *rt;
+	ListCell   *l;
+	ListCell   *rt;
 	Index		i;

 	CheckSelectForUpdate(qry);

-	if (lfirst(forUpdate) == NULL)
+	if (linitial(forUpdate) == NULL)
 	{
 		/* all regular tables used in query */
 		i = 0;
@ -2912,7 +2907,7 @@ transformForUpdate(Query *qry, List *forUpdate)
 					break;		/* out of foreach loop */
 				}
 			}
-			if (rt == NIL)
+			if (rt == NULL)
 				ereport(ERROR,
 						(errcode(ERRCODE_UNDEFINED_TABLE),
 						 errmsg("relation \"%s\" in FOR UPDATE clause not found in FROM clause",
@ -2938,7 +2933,7 @@ transformConstraintAttrs(List *constraintList)
 	Node	   *lastprimarynode = NULL;
 	bool		saw_deferrability = false;
 	bool		saw_initially = false;
-	List	   *clist;
+	ListCell   *clist;

 	foreach(clist, constraintList)
 	{
@ -3113,7 +3108,7 @@ analyzeCreateSchemaStmt(CreateSchemaStmt *stmt)
 {
 	CreateSchemaStmtContext cxt;
 	List	   *result;
-	List	   *elements;
+	ListCell   *elements;

 	cxt.stmtType = "CREATE SCHEMA";
 	cxt.schemaname = stmt->schemaname;